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| author | Marc-André Lureau <marcandre.lureau@redhat.com> | 2018-04-19 17:01:41 +0200 |
|---|---|---|
| committer | Markus Armbruster <armbru@redhat.com> | 2018-05-04 08:27:53 +0200 |
| commit | 7ee9edfdb117da47c86c9764d90f0be11a648666 (patch) | |
| tree | 76e597b01b87fa5c6707e6f6410cb347fefbb0b3 | |
| parent | 46cfbf13b06d551072ed17fbfca67c103edf814f (diff) | |
| download | qemu-7ee9edfdb117da47c86c9764d90f0be11a648666.zip qemu-7ee9edfdb117da47c86c9764d90f0be11a648666.tar.gz qemu-7ee9edfdb117da47c86c9764d90f0be11a648666.tar.bz2 | |
qobject: Ensure base is at offset 0
All QObject types have the base QObject as their first field. This
allows the simplification of qobject_to().
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180419150145.24795-2-marcandre.lureau@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message paragraph on type casts dropped, to avoid giving the
impression type casting would be okay]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
| -rw-r--r-- | include/qapi/qmp/qobject.h | 5 | ||||
| -rw-r--r-- | qobject/qobject.c | 9 |
2 files changed, 11 insertions, 3 deletions
diff --git a/include/qapi/qmp/qobject.h b/include/qapi/qmp/qobject.h index e022707..5206ff9 100644 --- a/include/qapi/qmp/qobject.h +++ b/include/qapi/qmp/qobject.h @@ -61,9 +61,8 @@ struct QObject { QEMU_BUILD_BUG_MSG(QTYPE__MAX != 7, "The QTYPE_CAST_TO_* list needs to be extended"); -#define qobject_to(type, obj) ({ \ - QObject *_tmp = qobject_check_type(obj, glue(QTYPE_CAST_TO_, type)); \ - _tmp ? container_of(_tmp, type, base) : (type *)NULL; }) +#define qobject_to(type, obj) \ + ((type *)qobject_check_type(obj, glue(QTYPE_CAST_TO_, type))) /* Initialize an object to default values */ static inline void qobject_init(QObject *obj, QType type) diff --git a/qobject/qobject.c b/qobject/qobject.c index 23600aa..87649c5 100644 --- a/qobject/qobject.c +++ b/qobject/qobject.c @@ -16,6 +16,15 @@ #include "qapi/qmp/qlist.h" #include "qapi/qmp/qstring.h" +QEMU_BUILD_BUG_MSG( + offsetof(QNull, base) != 0 || + offsetof(QNum, base) != 0 || + offsetof(QString, base) != 0 || + offsetof(QDict, base) != 0 || + offsetof(QList, base) != 0 || + offsetof(QBool, base) != 0, + "base qobject must be at offset 0"); + static void (*qdestroy[QTYPE__MAX])(QObject *) = { [QTYPE_NONE] = NULL, /* No such object exists */ [QTYPE_QNULL] = NULL, /* qnull_ is indestructible */ |